Athermogram identifies the warm and cool parts of an object by using

So we want to know what does the thermogram use to represent warm and cool parts of an object. So a thermogram is a representation of infrared electromagnetic waves better known as heat waves. So the correct answer is infrared electromagnetic waves or infrared waves.

Honestly "global warming" may be a slight possiblity, however they called it "climate change" because its not real, in fact we had one of our coldest days here not too long ago, and the "issues" with this subject is a blindfold for actual problems.